1. Field of the Invention
The invention relates to a glide path transmitter device for the instrument landing system (ILS) with a plurality of antenna radiators by way of which low-frequency modulated high-frequency signals, containing various carrier and side-band components, are emitted, which are superimposed in the Fraunhofer region, where they form a guide signal that can be analysed by aircraft, the phases of the carrier oscillations of the high-frequency signals to be emitted, which form the guide signal, being in fixed relation to one another.
2. Discussion of the Invention
In known systems of this type, especially in a so-called ILS M-type array and B-type array, carrier signals (CSB) and side-band signals (SBO) are emitted by way of antennae A1, A2 and A3 or A1 and A2 in the B-type array arranged at different heights above the ground. The signals are superimposed on one another in the Fraunhofer region where they form guide signals corresponding to the ILS standard, which can be analysed by aircraft. As is well-known, each antenna does not receive just one single signal component, rather a plurality of superimposed signal components has to be fed to some antennae. This is done by generating the required high-frequency signal in a feed network, that is a so-called load distributor, by adding the pure carrier signals (CSB) and side-band signals (SBO) already boosted to the required output power. Phase adjustments, which are necessary for the most precise setting possible of the glide path of the ILS system, especially when setting up the system for the first time, require phase shifters, that must be manually adjusted, arranged in proximity to the antennae. The load distributor is costly and prone to faults.